CVE-2026-104817

Misskey: Lack of rate limiting and size restrictions in RSS fetching API

State: Published
Severity: 8.7 High
Published: Oct 13, 2026
Updated: Oct 13, 2026
Reserved: Oct 2, 2026

Description

Misskey is an open source, federated social media platform. From 12.112.1 until 2026.7.0, the unauthenticated fetch-rss API lacks rate limiting and response-size restrictions and performs synchronous XML parsing. An attacker can trigger unbounded outbound HTTP requests and synchronous parsing, exhausting instance resources, amplifying requests toward third-party servers, or probing network-reachable services even when federation is disabled. This issue is fixed in version 2026.7.0.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:L/SI:N/SA:L	GitHub_M

Weaknesses

CWE-405 Asymmetric Resource Consumption (Amplification)
CWE-770 Allocation of Resources Without Limits or Throttling
CWE-918 Server-Side Request Forgery (SSRF)

Affected Products

Product	Versions
misskeymisskey-dev	>= 12.0.0, <= 13.14.2Affected >= 2023.9.0-beta.1, < 2026.7.0Affected

References

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